Of Joachim's genuine writings the one which, perhaps, attracted the most attention in his own day was a tract on the nature of the Trinity, attacking the definition of Peter Lombard, and asserting that it attributed a Quaternity to God. The subtleties of theology were dangerous, and in place of proving the Master of Sentences a heretic, Joachim himself narrowly escaped. Thirteen years after his death, the great Council of Lateran, in 1215, thought his speculation sufficiently important to condemn it as erroneous in an elaborate refutation, which was carried into the canon law, and Innocent III. preached a sermon on the subject to the assembled fathers. Fortunately Joachim, in 1200, had expressly submitted all his writings to the judgment of the Holy See and had declared that he held the same faith as that of Rome. The council, therefore, refrained from condemning him personally and expressed its approbation of his Order of Flora; but notwithstanding this the monks found themselves derided and insulted as the followers of a heretic, until, in 1220, they procured from Honorius III. a bull expressly declaring that he was a good Catholic, and forbidding all detraction of his disciples.[15] His most important writings, however, were his expositions of Scripture composed at the request of Lucius III., Urban III., and Clement III. Of these there were three--the Concordia, the Decachordon, or _Psalterium decem Cordarum_, and the _Expositio in Apocalypsin_. In these his system of exegesis is to find in every incident under the Old Law the prefiguration of a corresponding fact in chronological order under the New Dispensation, and by an arbitrary parallelism of dates to reach forward and ascertain what is yet to come. He thus determines that mankind is destined to live through three states--the first under the rule of the Father, which ended at the birth of Christ, the second under that of the Son, and the third under the Holy Ghost. The reign of the Son, or of the New Testament, he ascertains by varied apocalyptic speculations is to last through forty-two generations, or 1260 years--for instance, Judith remained in widowhood three years and a half, or forty-two months, which is 1260 days, the great number representing the years through which the New Testament is to endure, so that in the year 1260 the domination of the Holy Ghost is to replace it. In the forty-second generation there will be a purgation which will separate the wheat from the chaff--such tribulations as man has never yet endured: fortunately they will be short, or all flesh would perish utterly. After this, religion will be renewed; man will live in peace and justice and joy, as in the Sabbath which closed the labors of creation; all shall know God, from sea to sea, to the utmost confines of the earth, and the glory of the Holy Ghost shall be perfect. In that final abundance of spiritual grace the observances of religion will be no longer requisite.